Hot melt adhesive composition containing α-olefin/aromatic vinyl compound random copolymer

ABSTRACT

A hot melt adhesive composition exhibiting excellent adhesive strength and which is useful as an adhesive for styrene resins contains (B) tackifier and (C) ethylene/C3-C20 alpha-olefin/aromatic vinyl compound random copolymer and, in some embodiments also (A) base polymer, such as polyolefin, polar group-containing polymer and aromatic vinyl compound/conjugated diene copolymer. A low molecular weight polyolefin may also be included in all embodiments. The randon copolymer (C) may be prepared by polymerizing the alpha-olefin and aromatic vinyl compound in the presence of a metallocene containing catalyst. In addition to excellent adhesive strength the hot melt adhesives have improved workability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the Section 371 of International ApplicationPCT/JP98/00211, filed Jan. 21, 1998.

FIELD OF THE INVENTION

The present invention relates to a hot-melt adhesive composition. Moreparticularly, the present invention is concerned with a hot-meltadhesive composition which exhibits excellent adhesive strength and canbe used as an adhesive for styrene resins.

BACKGROUND OF THE INVENTION

It is well known that hot-melt adhesives comprising a base of a polymersuch as a polyolefin, a polyamide, a polyester, a vinyl acetatecopolymer, a cellulose derivative, polymethyl methacrylate, a polyvinylether or a polyurethane and, added to the base, a tackifier, exhibitadhesive effect when applied to, for example, a label, a kraft tape or acloth tape and heated.

In recent years, the fields of application of hot-melt adhesives arerapidly increasing because the hot-melt adhesives are superior to theconventional solvent containing adhesives in the coating speed, safety,working environment and energy saving. Commonly employed hot-meltadhesives comprise a base polymer of EVA or a styrene/conjugated dieneblock copolymer added to the base polymer, a tackifier and alow-molecular-weight polyolefin. Enhanced performance of adhesives isincreasingly demanded in recent years and it is required that adhesivesexhibit high adhesive strength to a variety of materials.

For example, specifically, the styrene content of the adhesive based onthe styrene/conjugated diene block copolymer is increased for improvingthe heat resistance of the adhesive. However, the adhesive strength ofthe resultant adhesive is not satisfactory, and it has been difficult torealize a desirable balance of heat resistance and adhesive property forthe adhesive.

OBJECT OF THE INVENTION

The present invention has been made in view of the above state of theprior art. It is an object of the present invention to provide ahot-melt adhesive composition having excellent adhesive strength.

SUMMARY OF THE INVENTION

The first hot-melt adhesive composition of the present inventioncomprises:

100 parts by weight of a tackifier (B), and

1 to 900 parts by weight of an α-olefin/aromatic vinyl compound randomcopolymer (C).

The second hot-melt adhesive composition of the present inventioncomprises:

100 parts by weight of a base polymer (A),

1 to 900 parts by weight of a tackifier (B), and

1 to 1000 parts by weight of an α-olefin/aromatic vinyl compound randomcopolymer (C).

The third hot-melt adhesive composition of the present inventioncomprises:

100 parts by weight of a base polymer (A),

10 to 300 parts by weight of a tackifier (B), and 10 to 400 parts byweight of an α-olefin/aromatic vinyl compound random copolymer (C).

In the present invention, the base polymer (A) is, for example, at leastone polymer selected from the group consisting of a polyolefin (a-1), apolar group containing polymer (a-2) and an aromatic vinylcompound/conjugated diene copolymer (a-3). Of these, the aromatic vinylcompound/conjugated diene copolymer (a-3) is preferred.

It is preferred in the present invention that the α-olefin/aromaticvinyl compound random copolymer (C) be an ethylene/aromatic vinylcompound random copolymer and that the α-olefin/aromatic vinyl compoundrandom copolymer (C) contain structural units derived from an aromaticvinyl compound in an amount of 1 to 80 mol %.

Further, the second and third hot-melt adhesive compositions of thepresent invention may comprise a low-molecular-weight polyolefin (D) inan amount of 1 to 100 parts by weight per 100 parts by weight of thebase polymer (A) in addition to the base polymer (A), the tackifier (B)and the α-olefin/aromatic vinyl compound random copolymer (C).

The first hot-melt adhesive composition of the present invention maycomprise a low-molecular-weight polyolefin having an intrinsic viscosity(η) of 0.01 to 0.6 dl/g (D) in an amount of 1 to 100 parts by weight per100 parts by weight of the tackifier (B) in addition to the tackifier(B) and the α-olefin/aromatic vinyl compound random copolymer (C).

DETAILED DESCRIPTION OF THE INVENTION

The hot-melt adhesive composition of the present invention will bedescribed in detail below.

The first hot-melt adhesive composition of the present inventioncomprises a tackifier (B) and an α-olefin/aromatic vinyl compound randomcopolymer (C) optionally together with a low-molecular-weight polyolefin(D).

Each of the second and third hot-melt adhesive compositions of thepresent invention comprises a base polymer (A), a tackifier (B) and anα-olefin/aromatic vinyl compound random copolymer (C) optionallytogether with a low-molecular-weight polyolefin (D).

First, each of the above components (A), (B), (C) and (D) for use in thepresent invention will be described.

Base Polymer (A)

The base polymer (A) added according to necessity in the presentinvention is not particularly limited as long as it is a polymergenerally employed in common hot-melt adhesives. Examples of suitablebase polymers (A) include a polyolefin (a-1), a polar group containingpolymer (a-2) and an aromatic vinyl compound/conjugated diene copolymer(a-3)

Polyolefin (a-1)

Examples thereof include:

polyethylenes (HDPE, LDPE, LLDPE, etc.);

polypropylenes (atactic polypropylene, syndiotactic polypropylene,etc.); and

ethylene/propylene copolymers.

Polar Group Containing Polymer (a-2)

Examples thereof include:

(1) ethylene/vinyl acetate copolymer (EVA);

(2) modified EVA polymers such as saponified EVA and graft-modified EVA;

(3) ethylene/(meth)acrylate copolymers such asethylene/ethyl(meth)acrylate (EEA);

(4) ionomer resins obtained by partially neutralizingethylene/(meth)acrylic acid copolymer, such as polymer conmerciallyavailable by the trade name of Himilan from Mitsui Du Pont Polychemical;

(5) ethylene/propylene/(meth)acrylic acid terpolymers;

(6) polyamides: products obtained by reacting a dibasic acid with adiamine, for example, those obtained by reacting a dimer acid which is adimer of a fatty acid such as soybean oil, tung oil or tall oil with analkyldiamine such as ethylenediamine or diethylenetriamine and nylonssuch as nylon-12, examples thereof including polymers commerciallyavailable by the trade name of Diamid (Daicel Chemical Industries,Ltd.), Platilon (Toagosei Chemical Industry Co., Ltd.) and Amilan (TorayIndustries, Inc.);

(7) polyesters, for example, those commercially available by the tradename of Ester Resin 200 or 300 (Toyobo Co., Ltd.) and Vitel 200 or 300(Goodyear Tire & Rubber Co., Ltd.); and

(8) vinyl acetate copolymers such as vinyl acetate/crotonic acidcopolymer, vinyl acetate/phthalic anhydride copolymer and vinylacetate/vinylpyrrolidone copolymer, cellulose derivative polymers,polymethyl methacrylate polymers, polyvinyl ether polymers, polyurethanepolymers and thermosetting resin polymers.

Aromatic Vinyl Compound/conjugated Diene Copolymer (a-3)

The aromatic vinyl compound/conjugated diene copolymer (a-3) is acopolymer of an aromatic vinyl compound and a conjugated diene compoundor a product of hydrogenation thereof. Examples thereof includestyrene/butadiene random copolymer, styrene/isoprene random copolymer,butadiene/polystyrene block copolymer, polystyrene/polyisoprene blockcopolymer, polystyrene/polyisoprene/polystyrene triblock copolymer,polystyrene/polybutadiene/polystyrene triblock copolymer,poly((α-methylstyrene)/polybutadiene/poly(α-methylstyrene) triblockcopolymer and products of hydrogenation thereof. These polymers, bothunhydrogenated and hydrogenated polymers, are commercially available.For example, such polymers are commercially available by the trade nameof Cariflex TR-1101, TR-1107 and TR-4113 (Shell Int. Chem. Co., Ltd.),Kraton G-6500, G-6521, G-1650, G-1652 and G-1657 (Shell Chem. Co., Ltd.)and Solprene and hydrogenated Solprene (Phillips Petroleum Co., Ltd.).

In the present invention, the above base polymers can be used eitherindividually or in combination. Of the above base polymers, the aromaticvinyl compound/conjugated diene copolymer and products of hydrogenationthereof are preferred. The aromatic vinyl compound/conjugated dienecopolymer is especially preferred.

Tackifier (B)

The tackifier (B) for use in the present invention is added forregulating the melt viscosity of the base polymer (A) and for improvingthe hot tack and wetting properties thereof. The tackifier (B) is notparticularly limited as long as, when blended with the base polymer (A)and heated, it can improve the hot tack and wetting properties of thebase polymer (A).

Examples of suitable tackifiers (B) include alicyclic hydrogenatedtackifiers, rosins (unmodified or modified rosin and products ofesterification thereof), aliphatic petroleum resins, alicyclic petroleumresins, aromatic petroleum resins, petroleum resins based on a copolymerof aliphatic and aromatic components, low-molecular-weight styreneresin, isoprene resin, alkyl phenolic resin, terpene resins andcoumaroneindene resin. These tackifiers (B) can be used eitherindividually or in combination in the present invention.

α-olefin/aromatic Vinyl Compound Random Copolymer (C)

The α-olefin/aromatic vinyl compound random copolymer (C) for use in thepresent invention is a random copolymer of an α-olefin and an aromaticvinyl compound. The α-olefin is, for example, selected from amongα-olefins having 2 to 20 carbon atoms, such as ethylene, propylene,1-butene, 3-methyl-1-butene, 4-methyl-1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene,1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene,1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicodecene. The aboveα-olefins can be used either individually or in combination.

Examples of suitable aromatic vinyl compounds include styrene; mono- orpolyalkylstyrenes such as o-methylstyrene, m-methylstyrene,p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene andp-ethylstyrene; functional group containing styrene derivatives such asmethoxystyrene, ethoxystyrene, vinylbenzoic acid, methyl vinylbenzoate,vinylbenzyl acetate, hydroxystyrene, o-chlorostyrene, p-chlorostyreneand divinylbenzene; 3-phenylpropylene, 4-phenylbutene andα-methylstyrene. Of these, styrene and 4-methoxystyrene are preferred.

The α-olefin/aromatic vinyl compound random copolymer (C) comprises 99.9to 20 mol %, preferably, 99 to 50 mol %, still preferably, 99 to 70 mol% of structural units derived from an α-olefin and 0.1 to 80 mol %,preferably, 1 to 50 mol %, still preferably, 1 to 30 mol % of structuralunits derived from an aromatic vinyl compound. When the content ofstructural units derived from an aromatic vinyl compound falls outsidethe above range, the adhesive property is likely to be poor.

It is preferred that the α-olefin/aromatic vinyl compound randomcopolymer (C) for use in the present invention be a random copolymer ofethylene, an aromatic vinyl compound and an (α-olefin having 3 to 20carbon atoms. Examples of suitable α-olefins having 3 to 20 carbon atomsinclude propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-butene,1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadeceneand 1-eicodecene. Of these, 1-butene, 1-pentene, 1-hexene and 1-octeneare preferred. The above α-olefins can be used either individually or incombination.

In the copolymer obtained from ethylene and an aromatic vinyl compoundoptionally together with an α-olefin, the molar ratio of structuralunits derived from ethylene to structural units derived from an α-olefinhaving 3 to 20 carbon atoms (ethylene/α-olefin) generally ranges from100/0 to 40/60, preferably, 100/0 to 60/40 and, still preferably, 100/0to 70/30.

When the molar ratio of structural units derived from ethylene tostructural units derived from an α-olefin having 3 to 20 carbon atoms isin the above range, excellent adhesive property is ensured.

In the copolymerization of the α-olefin/aromatic vinyl compound randomcopolymer, use may be made of another monomer, for example, anonconjugated diene. Examples of suitable nonconjugated dienes include1,4-pentadiene, 1,4-hexadiene, 4-methyl-1,5-heptadiene,5-methylene-2-norbornene, 5-ethylidene-2-norbornene,5-isopropenyl-2-norbornene, 2,5-norbornadiene, 1,6-cyclooctadiene,2-ethylene-2,5-norbornadiene, 2-isopropenyl-2,5-norbornadiene,dicyclopentadiene, 1,6-octadiene, 1,7-octadiene, tricyclopentadiene anddihydrodicyclopentadienyloxyethylene and further include esters withunsaturated carboxylic acids such as acrylic acid, methacrylic acid,itaconic acid, maleic acid and fumaric acid. These may be used eitherindividually or in combination.

It is preferred that the above α-olefin/aromatic vinyl compound randomcopolymer have an intrinsic viscosity (η), as measured in decalin at135° C., of 0.01 to 10 dl/g. When the intrinsic viscosity (η) is in therange of 0.01 to 0.6 dl/g, the resultant hot-melt adhesiveexhibits-satisfactory performance. When the intrinsic viscosity (η)exceeds 0.6 dl/g but is not greater than 10 dl/g, the workability (meltviscosity, stringing prevention) is improved to thereby facilitatehandling at the time of adding low-molecular-weight polymers.

In the α-olefin/aromatic vinyl compound random copolymer for use in thepresent invention, it is preferred from the viewpoint of adhesivestrength and handling easiness at the time of hot melting that the ratioof structural units constituting a chain structure in which at least twostructural units derived from an aromatic vinyl compound are arranged insequence be 1% or less, especially, 0.1% or less based on the structuralunits derived from the aromatic vinyl compound. The content of the chainstructure in which at least two structural units derived from anaromatic vinyl compound are arranged in sequence can be determined by¹³C-NMR.

When the α-olefin/aromatic vinyl compound random copolymer is anethylene/aromatic vinyl compound random copolymer, it is preferred thatthe B value determined by the ¹³C-NMR spectrum thereof and the followingformula range from 0.80 to 2.00, especially, from 0.85 to 1.50, stillespecially, from 0.95 to 1.45 and, further still especially, from 1.00to 1.40.

B value=(P_(SE))/(2−(P_(E))−(P_(S)))

wherein (P_(E)) represents the content, in terms of molar fraction, ofstructural units derived from ethylene (ethylene units) in theethylene/aromatic vinyl compound random copolymer, (P_(S)) representsthe content, in terms of molar fraction, of structural units derivedfrom the aromatic vinyl compound (aromatic vinyl compound units) in theethylene/aromatic vinyl compound random copolymer, and (P_(SE))represents the ratio of the number of aromatic vinyl compoundunit/ethylene unit chains to the total number of dyad chains in theethylene/aromatic vinyl compound random copolymer.

The B value determined by the above formula is an index indicating thestate of distribution of ethylene units and aromatic vinyl compoundunits in the copolymer. The B value can be determined with reference tothe reports of J. C. Randall (Macromolecules, 15, 353 (1982)) and J. Ray(Macromolecules, 10, 773 (1977)). The greater the above B value, theshorter the blocked chains of ethylene units or aromatic vinyl compoundunits, thereby indicating that the distribution of ethylene units andaromatic vinyl compound units is uniform. On the other hand, the smallerthan 1.00 the B value, the more nonuniform the distribution ofethylene/aromatic vinyl compound random copolymer, thereby indicatingthat the blocked chains are lengthened.

A process for producing the α-olefin/aromatic vinyl compound randomcopolymer will now be described.

The α-olefin/aromatic vinyl compound random copolymer for use in thepresent invention can be produced by copolymerizing ethylene and anaromatic vinyl compound optionally together with an α-olefin having 3 to20 carbon atoms, for example, in the presence of a metallocene catalyst(a).

Any of metallocene catalysts having been commonly used as a single sitecatalyst and metallocene catalyst similar thereto can be used as theabove metallocene catalyst (a) without any restriction. In particular,preferred use is made of a catalyst composed of a metallocene compoundof transition metal (transition metal compound) (b), an organoaluminumoxy compound (c) and/or an ionizing ionic compound (d).

Examples of suitable metallocene compounds (b) include metallocenecompounds of transition metals selected from among the elements of GroupIV of the periodic table (long period type) as indicated by groupnumbers 1 to 18 of revised issue (1989) of the IUPAC Inorganic ChemistryNomenclature, in particular, metallocene compounds represented by thefollowing general formula:

MLx  (1)

wherein M represents a transition metal selected from among the elementsof Group IV of the periodic table, for example, zirconium, titanium orhafnium, and x is the valence of the transition metal.

In the formula (1), L's represent ligands which coordinate with thetransition metal. Out of these, at least one ligand L has acyclopentadienyl skeleton. The ligand having a cyclopentadienyl skeletonTmay have substituents.

Examples of suitable ligands having a cyclopentadienyl skeleton includea cyclopentadienyl group; alkyl- or cycloalkyl-substitutedcyclopentadienyl groups such as a methylcyclopentadienyl group, anethylcyclopentadienyl group, an n- or i-propylcyclopentadienyl group, ann-, i-, sec- or t-butylcyclopentadienyl group, a hexylcyclopentaqdienylgroup, an octylcyclopentadienyl group, a dimethylcyclopentadienyl group,a trimethylcyclopentadienyl group, a tetramethylcyclopentadienyl group,a pentamethylcyclopentadienyl group, a methylethylcyclopentadienylgroup, a methylpropylcyclopentadienyl group, amethylbutylcyclopentadienyl group, a methylhexylcyclopentadienyl group,a methylbenzylcyclopentadienyl group, an ethylbutylcyclopentadienylgroup, an ethylhexylcyclopentadienyl group and amethylcyclohexylcyclopentadienyl group; and an indenyl group, a4,5,6,7-tetrahydroindenyl group and a fluorenyl group.

These groups may be substituted with halogen atoms, trialkylsilyl groupsand other groups.

Of these groups, alkyl-substituted cyclopentadienyl groups arepreferred.

When the metallocene compound (b) of the formula (1) has at least twocyclopentadienyl skeleton having groups as ligands L, two of thecyclopentadienyl skeleton having groups may be bonded with each otherthrough an alkylene group such as ethylene or propylene, a substitutedalkylene group such as isopropylidene or diphenylmethylene, a silylenegroup or a substituted silylene group such as dimethylsilylene,diphenylsilylene or methylphenylsilylene.

Examples of other L's than the cyclopentadienyl skeleton having ligandinclude a hydrocarbon group having 1 to 12 carbon atoms, an alkoxygroup, an aryloxy group, a sulfonic acid containing group of the formula—SO₃R¹ (wherein R¹ represents an alkyl group, an alkyl group substitutedwith a halogen atom, an aryl group or an aryl group substituted with ahalogen atom or an alkyl group), a halogen atom and a hydrogen atom.

Examples of suitable hydrocarbon groups having 1 to 12 carbon atomsinclude an alkyl group, a cycloalkyl group, an aryl group and an aralkylgroup. Specificaly, examples of suitable hydrocarbon groups include:

an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, decyl or dodecyl;

a cycloalkyl group such as cyclopentyl or cyclohexyl;

an aryl group such as phenyl or tolyl; and

an aralkyl group such as benzyl or neophyl.

Examples of suitable alkoxy groups include methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, pentoxy, hexoxyand octoxy.

Examples of suitable aryloxy groups include phenoxy.

Examples of suitable sulfonic acid containing groups of the formula—SO₃R¹ include methanesulfonate, p-toluenesulfonate,trifluoromethanesulfonate and p-chlorobenzenesulfonate.

Examples of suitable halogen atoms include fluorine, chlorine, bromineand iodine.

When the valence of the transition metal is, for example, 4, themetallocene compound (b) of the formula (1) can specifically berepresented by the general formula:

R² _(k)R³ ₁R⁴ _(m)R⁵ _(n)M  (2)

wherein M represents a transition metal, preferably, zirconium ortitanium as in the formula (1); R² represents a cyclopentadienylskeleton having group (ligand); R³, R⁴ and R⁵ may be identical with ordifferent from each other and are cyclopentadienyl skeleton havinggroups or the same as other L's than the cyclopentadienyl skeletonhaving ligands used in the formula (1); and k is an integer of 1 orgreater and satisfies the relationship k+1+m+n=4.

In the present invention, the metallocene compound (b) can be onerepresented by the general formula:

L¹M²Z¹ ₂  (3)

wherein:

M² represents a metal of Group IV or lanthanides series of the periodictable;

L¹ represents a derivative of delocalized n-bond group and imparts aconstrained geometric configuration to active sites of metal M²; and

Z¹s may be identical with or different from each other and represents ahydrogen atom, a halogen atom or any of a hydrocarbon group, a silylgroup and a germyl group which contain up to 20 carbon atoms, a siliconatom.and a germanium atom, respectively.

Of the above metallocene compounds (b) of the formula (3), preferred useis made of the metallocene compound represented by the general formula:

In the above formula (4), M³ represents titanium, zirconium or hafnium,and Z¹ is as defined above.

Cp represents an unsubstituted or a substituted cyclopentadienyl groupor a derivative thereof, which is π-bonded in η0 ⁵ bonding form to M³.

W¹ represents oxygen, sulfur, boron, an element of Group 14 of theperiodic table or a group containing any of these elements.

V¹ represents a ligand containing nitrogen, phosphorus, oxygen orsulfur.

W¹ and V¹ may form a condensed ring, and Cp and W¹ may form a condensedring.

Preferred examples of groups represented by Cp of the general formula(4) include a cyclopentadienyl group, an indenyl group, a fluorenylgroup and saturated derivatives thereof. These form rings in cooperationWith metal atom (M³). Each carbon atom in the cyclopentadienyl group maybe substituted or unsubstituted with the same or a different groupselected from the group consisting of hydrocarbyl groups,substituted-hydrocarbyl groups wherein one or more hydrogen atoms isreplaced by a halogen atom, hydrocarbyl substituted metalloid groupswherein the metalloid is selected from Group 14 of the Periodic Table ofthe Elements, and the halogen groups. Two or a plurality of suchsubstituents in combination may form a fused ring system. Preferredunsubstituted or substituted hydrocarbyl groups capable of substitutingat least one hydrogen atom in the cyclopentadienyl group each contain 1to 20 carbon atoms and include linear or branched alkyl groups, cyclichydrocarbon groups, alkyl substituted cyclic hydrocarbon groups,aromatic groups and alkyl substituted aromatic groups. Examples ofpreferred organometalloid groups include mono-, di- and tri-substitutedorganometalloid groups of the elements of Group 14. Each of thehydrocarbyl groups contains 1 to 20 carbon atoms. Specific examples ofpreferred organometalloid groups include trimethylsilyl, triethylsilyl,ethyldimethylsilyl, methyldiethylsilyl, phenyldimethylsilyl,methyldiphenylsilyl, triphenylsilyl, triphenylgermyl andtrimethylgermyl.

Z¹s of the general formula (4) each represent, for example, a hydride, ahalo, an alkyl, a silyl, a germyl, an aryl, an amide, an aryloxy, analkoxy, a phosphide, a sulfide, an acyl, a pseudohalide such as acyanide or an azide, an acetylacetonate or a mixture thereof, which maybe either identical with or different from each other.

Examples of the compounds represented by the general formula (4)include:

(dimethyl(t-butylamido)(tetramethyl-η⁵-cyclopentadienyl) silane)titaniumdichloride; and ((t-butylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediyl)titanium dichloride.

Among the various metallocene compounds (b), the metallocene compoundrepresented by the general formula (3) is especially preferred from theviewpoint of polymerization activity and the transparency, rigidity,heat resistance and impact resistance of molded item. The abovedescribed metallocene compounds (b) may be used either individually orin combination.

Each of the metallocene compounds (b) for use in the present inventionmay be diluted with a hydrocarbon or a halogenated hydrocarbon prior touse.

The organoaluminum oxy compound (c) and ionizing ionic compound (d) foruse in the formation of the metallocene catalyst (a) will be describedbelow.

The organoaluminum oxy compound (c) for use in the present invention maybe conventional aluminooxane (c) or benzene-insoluble organoaluminum oxycompounds (c) set forth by way of example in Japanese Patent Laid-openPublication No. 2(1990)-78687.

The aluminooxane (c) is produced, for example, by the following methodsand is generally recovered as a solution in a hydrocarbon solvent:

method (1) in which an organoaluminum compound such as atrialkylaluminum is added to an aromatic hydrocarbon solvent in which anadsorbed water containing compound or crystal water containing salt suchas magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfatehydrate, nickel sulfate hydrate or cerium (I) chloride hydrate issuspended and reacted, and the product is recovered as a solution in thearomatic hydrocarbon solvent;

method (2) in which water (liquid water, ice or steam) directly acts onan organoaluminum compound such as a trialkylaluminum in a solvent suchas benzene, toluene, ethyl ether or tetrahydrofuran, and the product isrecovered as a solution in an aromatic hydrocarbon solvent; and

method (3) in which an organotin oxide such as dimethyltin oxide ordibutyltin oxide reacts with an organoaluminum compound such as atrialkylaluminum in a hydrocarbon solvent such as decane, benzene ortoluene.

Examples of suitable ionizing ionic compounds (d) include Lewis acids,ionic compounds, borane compounds and carborane compounds. Theseionizing ionic compounds (d) are described in Published JapaneseTranslation of PCT Patent Applications from Other States, Nos.1(1989)-501950 and 1(1989)-502036, Japanese Patent Laid-open PublicationNos. 3(1991)-179005, 3(1991)-179006, 3(1991)-207703 and 3(1991)-207704and U.S. Pat. No. 5,321,106.

The Lewis acid used as ionizing ionic compound (d) is, for example, anyof compounds represented by the formula BR₃ (wherein R's may beidentical with or different from each other and represent fluorine atomsor phenyl groups unsubstituted or substituted with a fluorine atom, amethyl group, a trifluoromethyl group or the like). Examples of suitableLewis acids include trifluoroboron, triphenylboron,tris(4-fluorophenyl)boron, tris(3,5-difluorophenyl)boron,tris(4-fluoromethylphenyl)boron and tris(pentafluorophenyl)boron.

The ionic compound used as ionizing ionic compound (d) is a saltconsisting of a cationic compound (cation) and an anionic compound(anion). The anionic compound reacts with the above metallocene compound(b) to thereby cationize the metallocene compound (b) and thus form anion pair, so that the anionic compound acts to stabilize transitionmetal cation species. Examples of suitable anions include organoboroncompound anions, organoarsenic compound anions and organoaluminumcompound anions. Of these, relatively bulky anions capable ofstabilizing transition metal cation species are preferred. Examples ofsuitable cations include metal cations, organometal cations, carboniumcations, tritium cations, oxonium cations, sulfonium cations,phosphonium cations and ammonium cations. Specifically, suitable cationsinclude triphenylcarbenium cation, tributylammonium cation,N,N-dimethylammonium cation and ferrocenium cation.

Of the above compounds, ionic compounds containing a boron compound arepreferably used as the anionic compound, which include, for example,trialkylsubstituted ammonium salts, N,N-dialkylanilinium salts,dialkylammonium salts and triarylphosphonium salts.

Examples of the above trialkyl-substituted ammonium salts includetriethylammonium tetra(phenyl)boride, tripropylammoniumtetra(phenyl)boride, tri(n-butyl) ammonium tetra(phenyl)boride andtrimethylammonium tetra(p-tolyl)boride.

Examples of the above N,N-dialkylanilinium salts includeN,N-dimethylanilinium tetra(phenyl)boride.

Examples of the above dialkylammonium salts include di(n-propyl)ammoniumtetra(pentafluorophenyl)boride and dicyclohexylammoniumtetra(phenyl)boride.

Examples of the above triarylphosphonium salts includetriphenylphosphonium tetra(phenyl)boride, tri(methylphenyl) phosphoniumtetra(phenyl)boride and tri(dimethylphenyl) phosphoniumtetra(phenyl)boride.

Moreover, triphenylcarbenium tetrakis(pentafluorophenyl)borate,N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate, ferroceniumtetra(pentafluorophenyl) borate and the like can be mentioned as theabove ionic compounds.

Examples of the borane compounds used as ionizing ionic compound (d)include:

decaborane (14);

anion salts such as bis(tri(n-butyl)a monium) nonaborate andbis(tri(n-butyl)ammonium) decaborate; and

metal borane anion salts such as tri(n-butyl)ammoniumbis(dodecahydridedodecaborate) cobalt acid salt (III) andbis(tri(n-butyl)ammonium) bis(dodecahydridedodecaborate) nickel acidsalt (III).

Examples of the carborane compounds used as ionizing ionic compound (d)include:

anion salts such as 4-carbanonaborane (14) and 1,3-dicarbanonaborane(13); and

metal carborane anion salts such as tri(n-butyl)ammoniumbis(nonahydride-1,3-dicarbanonaborate) cobalt acid salt (III) andtri(n-butyl)ammonium bis(undecahydride-7,8-dicarbaundecaborate) ironacid salt (III).

The above ionizing ionic compounds (d) may be used in combination.

The metallocene catalyst (a) for use in the present invention maycontain the following organoaluminum compound (e) in addition to theabove components, according to necessity.

The organoaluminum compound (e) employed according to necessity is, forexample, the organoaluminum compound represented by the general formula:

(R⁶)_(n)AlX_(3−n)  (5).

In the formula (5), R⁶ represents a hydrocarbon group having 1 to 15,preferably, 1 to 4 carbon atoms; X represents a halogen atom or ahydrogen atom; and n is 1 to 3.

Examples of suitable hydrocarbon groups each having 1 to 15 carbon atomsinclude alkyl groups, cycloalkyl groups and aryl groups. Specifically,use is made of, for example, a methyl, an ethyl, an n-propyl, anisopropyl or an isobutyl group.

Examples of suitable organoaluminum compounds include:

trialkylaluminums such as trimethylaluminum, triethylaluminum,triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum andtri-sec-butylaluminum;

alkenylaluminums such as isoprenylaluminum, represented by the generalformula:

(i—C₄H₉)_(x)Al_(y)(C₅H₁₀)_(z)

wherein x, y and z are positive numbers, and z and x satisfy therelationship z≧2x;

dialkylaluminum halides such as dimethylaluminum chloride anddiisobutylaluminum chloride;

dialkylaluminum hydrides such as diisobutylaluminum hydride;

dialkylaluminum alkoxides such as dimethylaluminum methoxide; and

dialkylaluminum aryloxides such as diethylaluminum phenoxide.

The copolymerization of ethylene and the aromatic vinyl compoundoptionally together with the α-olefin having 3 to 20 carbon atoms may beconducted by either the batch process or the continuous process. Whenthe copolymerization is conducted by the continuous process, themetallocene catalyst (a) is used in the following concentration.

That is, the concentration of metallocene compound (b) in thepolymerization system generally ranges from 0.00005 to 1.0 mmol/lit.,preferably, 0.0001 to 0.5 mmol/lit. (polymerization volume).

The organoaluminum oxy compound (c) is fed in an amount of 0.1 to10,000, preferably, 1 to 5,000 in terms of the ratio of aluminum atomsto transition metal in metallocene compound (b) (Al/transition metal) inthe polymerization system.

The ionizing ionic compound (d) is fed in an amount of 0.1 to 20,preferably, 1 to 10 in terms of the molar ratio of ionizing ioniccompound (d) to metallocene compound (b) in the polymerization system(ionizing ionic compound (d)/metallocene compound (b)).

When the organoaluminum compound (e) is used, it is generally fed in anamount of about 0 to 5 mmol/lit., preferably, about 0 to 2 mmol/lit.(polymerization volume).

The copolymerization reaction for producing the α-olefin/aromatic vinylcompound random copolymer is generally conducted at a temperature of −30to 250° C., preferably, 0 to 200° C. under a pressure of 0 to 80 kg/cm²,preferably, 0 to 50 kg/cm² (gauge pressure).

Although depending on the catalyst concentration, polymerizationtemperature and other conditions, the reaction time (average residencetime when the copolymerization is carried out by the continuous process)generally ranges from 5 min to 3 hr, preferably, from 10 min to 1.5 hr.

In the production of the α-olefin/aromatic vinyl compound randomcopolymer, ethylene and the aromatic vinyl compound optionally togetherwith the α-olefin having 3 to 20 carbon atoms are fed to thepolymerization system in such amounts that the copolymer with the abovespecified compositions can be obtained. Further, a molecular weightregulator such as hydrogen can be employed in the copolymerization.

When ethylene and the aromatic vinyl compound optionally together withthe α-olefin having 3 to 20 carbon atoms are copolymerized in the abovemanner, the α-olefin/aromatic vinyl compound random copolymer isobtained as a polymer solution containing the same. The polymer solutionis processed according to the customary procedure. Thus, there isobtained the α-olefin/aromatic vinyl compound random copolymer.

A graft copolymerization of a monoolefindicarboxylic acid or ananhydride thereof may be conducted on the above α-olefin/aromatic vinylcompound random copolymer (C). Examples of suitablemonoolefindicarboxylic acids and anhydrides thereof include dicarboxylicacids such as maleic acid, fumaric acid, itaconic acid, crotonic acid,isocrotonic acid, citraconic acid, acrylsuccinic acid, mesaconic acid,glutaconic acid, Nadic acid(endocisbicyclo(2.2.1)hept-2-ene-5,6-dicarboxylic acid), methyl Nadicacid, tetrahydrophthalic acid and methylhexahydrophthalic acid; andanhydrides such as allylsuccinic anhydride, glutaconic anhydride, Nadicanhydride and tetrahydrophthalic anhydride. At least one of these may becontained in the form of graft units in the graft-modifiedα-olefin/aromatic compound random copolymer.

It is preferred that the degree of graft modification by themonoolefindicarboxylic acid or anhydride thereof range from 0.1 to 20%by weight, especially, 0.5 to 10% by weight from the viewpoint that ahot-melt adhesive improved in stringing prevention and having excellentworkability can be obtained from the graftmodified α-olefin/aromaticvinyl compound random copolymer. Herein, the graft modification degreemeans the ratio of graft copolymerized monomer to backbone polymer onwhich a graft copolymerization is carried out. For example, when 1 g ofmonomer is graft copolymerized on 100 g of the backbone polymer, thegraft modification degree is 1% by weight.

The graft modification of the α-olefin/aromatic vinyl compound randomcopolymer can be conducted by the customary method (for example, themethod described in Japanese Patent Publication No. 52(1977)-22988). Forexample, the graft modification can be carried out by the methodcomprising heating the (α-olefin/aromatic vinyl compound randomcopolymer at temperature higher than the softening point to thereby meltthe same and slowly dropping thereto the monoolefindicarboxylic acid oranhydride thereof and a peroxide simultaneously under agitation tothereby carry out a graft copolymerization.

Low-molecular-weight Polyolefin (D)

Examples of suitable low-molecular-weight polyolefins (D) addedaccording to necessity in the present invention include:

(i) a polyolefin having an intrinsic viscosity (η) of 0.01 to 0.6 dl/gwhich is a homopolymer of one of α-olefins having 2 to 12 carbon atomsor a copolymer of at least two thereof; and

(ii) a saturated linear or saturated branched hydrocarbon whoseintrinsic viscosity (η) ranges from 0.01 to 0.6 dl/g.

With respect to the polyolefin (i), examples of suitable α-olefinshaving 2 to 12 carbon atoms include ethylene, propylene, 1-butene,1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene,3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene,1-heptene, methyl-1-hexene, dimethyl-1-pentene, trimethyl-1-butene,ethyl-1-pentene, 1-octene, dimethyl-1-hexene, trimethyl-1-pentene,ethyl-1-hexene, methylethyl-1-pentene, diethyl-1-butene,propyl-1-pentene, 1-decene, methyl-1-nonene, dimethyl-1-octene,trimethyl-1-heptene, ethyl-1-octene, methylethyl-1-heptene,diethyl-1-hexene and 1-dodecene.

The polyolefin (i) can be produced by various conventional methods.Examples thereof include the method employing a high pressure radicalpolymerization or a low or medium pressure polymerization conducted inthe presence of various transition metal compound catalysts such asZiegler catalyst and the thermal decomposition method in which, afterthe formation of a high-molecular-weight homopolymer or copolymer by theabove polymerization method, the molecular weight of thehigh-molecular-weight homopolymer or copolymer is reduced by the thermaldegradation technique or the radical degradation technique using aperoxide.

Examples of suitable hydrocarbons (ii) include linear hydrocarbons(e.g., paraffin wax and Sasol wax) and branched hydrocarbons (e.g.,microwax). These waxes are publicly known and commercially available.

For example, Sasol wax can be produced by the following process.

For example, coal is gasified by the use of steam and oxygen to therebyobtain a synthetic gas composed mainly of carbon monoxide and hydrogen.This synthetic gas is passed through a fixed bed catalyst reactor inaccordance with the process known as “ARGE process”. Out of the thusobtained reaction product, the fraction heavier than diesel engine oilis separated into the first fraction (components of C₁₈ to C₂₃), thesecond fraction (components of C₂₂ to C₃₆) and the third fraction(components of C₃₃ and higher) by vacuum distillation. The thirdfraction is hydrogenated and all unsaturated hydrocarbons and oxygencompounds are removed. Thus, Sasol wax is obtained.

Hot-melt Adhesive Composition

The first hot-melt adhesive composition of the present inventioncomprises the above tackifier (B) and α-olefin/aromatic vinyl compoundrandom copolymer (C). Specifically, the first hot-melt adhesivecomposition comprises:

100 parts by weight of the tackifier (B), and 1 to 900 parts by weight,preferably, 1 to 700 parts by weight of the α-olefin/aromatic vinylcompound random copolymer (C).

The second hot-melt adhesive composition of the present inventioncomprises the above base polymer (A), tackifier (B) andα-olefin/aromatic vinyl compound random copolymer (C). Specifically, thesecond hot-melt adhesive composition comprises:

100 parts by weight of the base polymer (A),

1 to 900 parts by weight, preferably,

1 to 700 parts by weight of the tackifier (B), and

1 to 1,000 parts by weight, preferably, 1 to 800 parts by weight of theα-olefin/aromatic vinyl compound random copolymer (C).

That is, the second hot-melt adhesive composition contains more than 0to 10,000 parts by weight, preferably, 15 to 10,000 parts by weight ofthe base polymer (A) and 0.1 to 100,000 parts by weight, preferably, 0.1to 80,000 parts by weight of the α-olefin/aromatic vinyl compound randomcopolymer (C) per 100 parts by weight of the tackifier (B).

The third hot-melt adhesive composition of the present inventioncomprises the above base polymer (A), tackifier (B) andα-olefin/aromatic vinyl compound random copolymer (C). Specifically, thethird hot-melt adhesive composition comprises:

100 parts by weight of the base polymer (A),

10 to 300 parts by weight, preferably, 50 to 200 parts by weight of thetackifier (B), and

10 to 400 parts by weight, preferably, 30 to 300 parts by weight of theα-olefin/aromatic vinyl compound random copolymer (C).

Low-molecular-weight polyolefin (D) can be blended into the firsthot-melt adhesive composition of the present invention in an amount of 1to 100 parts by weight, preferably, 10 to 80 parts by weight per 100parts by weight of the tackifier (B).

Low-molecular-weight polyolefin (D) can be blended into the secondhot-melt adhesive composition of the present invention in an amount of 1to 100 parts by weight, preferably, 10 to 80 parts by weight per 100parts by weight of the base polymer (A).

Low-molecular-weight polyolefin (D) can be blended into the thirdhot-melt adhesive composition of the present invention in an amount of 1to 100 parts by weight, preferably, 10 to 80 parts by weight per 100parts by weight of the base polymer (A). In any of the first, second andthird hot-melt adhesive compositions, the blending oflow-molecular-weight polyolefin (D) lowers the melt viscosity of thehot-melt adhesive composition to thereby enable further enhancing theworkability of the hot-melt adhesive composition. When thelow-molecular-weight polyolefin (D) is blended, it is preferred that theintrinsic viscosity (η) of the α-olefin/aromatic vinyl compound randomcopolymer be greater than 0.6 dl/g but not greater than 10 dl/g.

In addition to the above base polymer (A), tackifier(B),α-olefin/aromatic vinyl compound random copolymer (C) andlow-molecular-weight polyolefin (D), according to necessity, variousadditives such as a softener, a stabilizer, a filler and an antioxidantcan be blended into the hot-melt adhesive composition of the presentinvention in amounts not detrimental to the object of the presentinvention.

The second and third hot-melt adhesive compositions of the presentinvention can be produced by the common process. For example, the abovebase polymer (A), tackifier(B) and α-olefin/aromatic vinyl compoundrandom copolymer (C) optionally together with the-low-molecular-weightpolyolefin (D) and various additives are fed into a blender such asBrabender Plastograph in given proportions, heated and melt kneaded, andshaped into desired configuration, e.g., granules, flakes or rods. Thefirst hot-melt adhesive composition of the present invention can also beproduced by the same process using the tackifier (B) andα-olefin/aromatic vinyl compound random copolymer (C).

The hot-melt adhesive composition of the present invention is heated,melted and applied, according to the customary procedure, onto amaterial to be coated, such as cloth, kraft paper, aluminum foil orother metal foil, polyester film or other resin molding to thereby forman adhesive layer on the material prior to use.

The hot-melt adhesive composition of the present invention exhibitsexcellent adhesive properties even when it is used in bonding a styrenepolymer with a polyolefin.

EFFECT OF THE INVENTION

The hot-melt adhesive composition of the present invention exhibitsexcellent workability and high adhesive strength.

EXAMPLE

The present invention will now be further illustrated with reference tothe following Examples, which in no way limit the scope of theinvention.

Production Example 1

Production of Ethylene/styrene Random Copolymer

A 1 lit. glass reactor equipped with a condenser and an agitator wassatisfactorily purged with nitrogen, charged with 494 ml of toluene and6 ml of styrene and saturated with ethylene under agitation.Subsequently, the system interior was heated to 35° C., and 4.5 mmol ofmethylaluminooxane (produced by Tosoh Akzo, 10% by weight toluenesolution) and 0.045 mmol of (t-butyl-amido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silane-titanium dichloride (0.01 mmoltoluene solution) were added to the mixture. A polymerization wasconducted at 40° C. for 60 min while continuously feeding ethylene at arate of 100 Nlit./hr. After the completion of the polymerization, 250 mlof isobutyl alcohol and 10 ml of aqueous hydrochloric acid were added tothe mixture and heated at 80° C. for 30 min under agitation. Theobtained reaction mixture containing isobutyl alcohol was transferred toa separating funnel, washed with 250 ml of water twice and separatedinto an oil phase and a water phase. The oil phase was poured into 3lit. of methanol to thereby precipitate a polymer. The precipitated andseparated polymer was dried in vacuum at 130° C. for 12 hr, therebyobtaining an ethylene/styrene random copolymer (hereinafter referred toas “ESC-1”). The molar ratio of ESC-1 constituting ethylene units tostyrene units (ethylene units/styrene units) was 97/3, and the ESC-1exhibited an intrinsic viscosity (7) of 1.6 dl/g as measured in decalinat 135° C.

Production Example 2

Production of Ethylene/styrene Random Copolymer

20 g of ESC-1 obtained in Production Example 1 was placed in a 50 mlpyrex tube and the interior thereof was satisfactorily purged withnitrogen. The pyrex tube was mounted on an aluminum block heater heatedat 380° C. and the heating was continued in a nitrogen atmosphere for aperiod of 60 min started 5 min after the mounting of the pyrex tube.Thereafter, a natural cooling was performed, thereby obtaining a waxyethylene/styrene random copolymer (hereinafter referred to as “ESC-2”).The molar ratio of ESC-2 constituting ethylene units to styrene units(ethylene units/styrene units) was 97/3, and the ESC-2 exhibited anintrinsic viscosity (η) of 0.2 dl/g as measured in decalin at 135° C.The yield was 99.2%.

Production Example 3

Production of Ethylene/styrene Random Copolymer

An ethylene/styrene random copolymer (ESC-3) was obtained in the samemanner as in Production Example 1 except thatisopropylidene-bis(indenyl)zirconium dichloride synthesized by theconventional process was used in place of(t-butylamido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanetitaniumdichloride. The molar ratio of ESC-3 constituting ethylene units tostyrene units (ethylene units/styrene units) was 96/4, and the ESC-3exhibited an intrinsic viscosity (η) of 1.3 dl/g as measured in decalinat 135° C.

Production Example 4

Production of Ethylene/styrene Random Copolymer

The same procedure as in Production Example 2 was repeated except thatthe copolymer (ESC-3) produced in Production Example 3 was used as thecopolymer. Thus, there was obtained an ethylene/styrene random copolymer(hereinafter referred to as “ESC-4”). The molar ratio of ESC-4constituting ethylene units to styrene units (ethylene units/styreneunits) was 96/4, and the ESC-4 exhibited an intrinsic viscosity (η) of0.2 dl/g as measured in decalin at 135° C.

Production Example 5

Production of Ethylene/styrene Random Copolymer

An ethylene/styrene random copolymer (hereinafter referred to as“ESC-5”) was produced in the same manner as in Production Example 1except that the amounts of toluene and styrene were changed to 485 mland 15 ml, respectively. The molar ratio of ESC-5 constituting ethyleneunits to styrene units (ethylene units/styrene units) was 88/12, and theESC-5 exhibited an intrinsic viscosity (η) of 1.5 dl/g as measured indecalin at 135° C.

Example 1

25 g of styrene/ethylene/butylene/styrene block copolymer (trade name:Kraton G1657, produced by Shell Chem. Co., Ltd., hereinafter referred toas “SEBS”), 15 g of ESC-1 obtained in Production Example 1, 40 g ofaliphatic petroleum resin (trade name: Hi-rez T-500X, produced by MitsuiPetrochemical Industries, Ltd., hereinafter referred to as “petroleumresin H”) and 20 g of Sasol wax (trade name: Sasol HI imported by S.Kato & Company) as a low-molecular-weight polyolefin were melt kneadedat 180° C., thereby obtaining a hot-melt adhesive composition.

The obtained hot-melt adhesive composition was applied onto aluminumfoils (50 μm) each in a thickness of 15 μm, and coating surfaces wereattached to each other. Heat sealing was performed by a heat sealingmachine under conditions such that the upper bar temperature, the lowerbar temperature, the application pressure and the pressurization timewere 170° C., 70° C., 1 kg/cm² and 2 sec, respectively, therebyobtaining a laminate sheet. This laminate sheet was cut into specimenseach with a width of 25 mm. A 180° peeling test was conducted by meansof a tensile tester at a pulling rate of 300 mm/sec to thereby measurean adhesive strength.

The results are given in Table 1.

Comparative Example 1

The same procedure as in Example 1 was repeated except that the amountof SEBS was changed to 40 g and no use was made of ESC-1.

The results are given in Table 1.

Example 2

The same procedure as in Example 1 was repeated except that aliphaticpetroleum resin (trade name: Petrosin, produced by Mitsui PetrochemicalIndustries, Ltd., hereinafter referred to as “petroleum resin P”) wasused in place of the petroleum resin H.

The results are given in Table 1.

Comparative Example 2

The same procedure as in Comparative Example 1 was repeated except thatthe petroleum resin P was used in place of the pentene-based aliphaticpetroleum resin.

The results are given in Table 1.

Example 3

The same procedure as in Example 1 was repeated except that 40 g ofSEBS, 40 g of petroleum resin H and 20 g of ESC-2 were employed as thecomposition components.

The results are given in Table 1.

Example 4

The same procedure as in Example 1 was repeated except that 40 g ofSEBS, 40 g of petroleum resin P and 20 g of ESC-2 were employed as thecomposition components.

The results are given in Table 1.

Example 5

The same procedure as in Example 1 was repeated except that thecopolymer ESC-3 produced in Production Example 3 was used as thecopolymer component.

The results are given in Table 1.

Example 6

The same procedure as in Example 3 was repeated except that thecopolymer ESC-4 produced in Production Example 4 was used as thecopolymer component.

The results are given in Table 1.

TABLE 1 Formulation of Adhesive strength hot-melt adhesive (N/25 mm)composition (g) 0° C. 20° C. 40° C. Ex. 1 SEBS 25 5.1 9.0 14.2 Petroleumresin-H 40 ESC-1 15 Sasol wax 20 Com. Ex. 1 SEBS 40 3.3 4.0 10.7Petroleum resin-H 40 Sasol wax 20 Ex. 2 SEBS 25 4.8 8.8 13.0 Petroleumresin-P 40 ESC-1 15 Sasol wax 20 Com. Ex. 2 SEBS 40 2.5 3.5 10.1Petroleum resin-P 40 Sasol wax 20 Ex. 3 SEBS 40 4.6 8.0 12.3 Petroleumresin-H 40 ESC-2 20 Ex. 4 SEBS 40 4.0 7.1 11.8 Petroleum resin-P 40ESC-2 20 Ex. 5 SEBS 25 4.8 8.8 13..5 Petroleum resin-H 40 ESC-3 15 Sasolwax 20 Ex. 6 SEBS 40 4.1 7.5 11.5 Petroleum resin-H 40 ESC-4 20

Example 7

40 g of copolymer ESC-5 obtained in Production Example 5 and 80 g of C9hydrogenated petroleum resin (trade name: Arkon P-100, produced byArakawa Chemicals, INC.) were melt kneaded, thereby obtaining a hot-meltadhesive composition. This hot-melt adhesive composition was formed intoa laminate sheet as a test specimen and subjected to the peeling test inthe same manner as in Example 1. The thus measured adhesive strengthswere 4.0 N/25 mm at 0° C., 7.1 N/25 mm at 20° C., 18.6 N/25 mm at 40° C.and 32.8 N/25 mm at 60° C.

The results are collectively given in Table 2.

Example 8

A hot-melt adhesive composition and a laminate sheet were produced and apeeling test conducted in the same manner as in Example 7, except thataromatic hydrocarbon resin (trade name: FTR 6100, produced by MitsuiChemical Industries, Ltd.) was used in place of the C9 hydrogenatedpetroleum resin. The thus measured adhesive strengths were 5.7 N/25 mmat 0° C., 9.8 N/25 mm at 20° C., 26.3 N/25 mm at 40° C. and 34.0 N/25 mmat 60° C.

The results are collectively given in Table 2.

Comparative Example 3

A hot-melt adhesive composition and a laminate sheet were produced and apeeling test conducted in the same manner as in Example 7, except thathydrogenated styrene/butadiene/styrene triblock copolymer (trade name:Kraton G1657, produced by Shell Chem. Co., Ltd.) was used in place ofthe copolymer ESC-5 obtained in Production Example 5. The thus measuredadhesive strengths were 5.3 N/25 mm at 0° C., 12.3 N/25 mm at 20° C.,10.4 N/25 mm at 40° C. and 9.7 N/25 mm at 60° C.

The results are collectively given in Table 2.

Comparative Example 4

A hot-melt adhesive composition and a laminate sheet were produced and apeeling test conducted in the same manner as in Example 8, except thathydrogenated styrene/butadiene/styrene triblock copolymer (trade name:Kraton G1657, produced by Shell Chem. Co., Ltd.) was used in place ofthe copolymer ESC-5 obtained in Production Example 5. The thus measuredadhesive strengths were 2.7 N/25 mm at 0° C., 4.6 N/25 mm at 20° C., 5.6N/25 mm at 40° C. and 2.6 N/25 mm at 60° C. The results are collectivelygiven in Table 2.

TABLE 2 Adhesive strength Formulation of hot melt (unit of N/25 mm)adhesive composition (g) 0° C. 20° C. 40° C. 60° C. Ex. 7 C9hydrogenated 80 4.0 7.1 18.6 32.8 petroleum resin ESC-5 40 Ex. 8Aromatic hydrocarbon 80 5.7 9.8 26.3 34.0 resin ESC-5 40 Com. C9hydrogenated 80 5.3 12.3 10.4 9.7 Ex. 3 petroleum resin Hydrogenatedstyrene/ 40 butadiene/styrene triblock copolymer Com. Aromatichydrocarbon 80 2.7 4.6 5.6 2.6 Ex. 4 resin Hydrogenated styrene/ 40butadiene/styrene triblock copolymer

What is claimed is:
 1. A hot melt adhesive composition comprising: 100parts by weight of tackifier (B), and 1 to 900 parts by weight ofethylene/α-olefin/aromatic vinyl compound random copolymer (C), whereinin random copolymer (C), the α-olefin has from 3 to 20 carbon atoms, andthe molar ratio of structural units derived from ethylene to structuralunits derived from α-olefin having 3 or more carbon atoms(ethylene/α-olefin) is in the range of from 100/0 to 40/60.
 2. A hotmelt adhesive composition comprising: 100 parts by weight of basepolymer (A), 1 to 900 parts by weight of tackifier (B), and 1 to 1000parts by weight of ethylene/α-olefin/aromatic vinyl compound randomcopolymer (C), wherein, in random copolymer (C), the α-olefin has from 3to 20 carbon atoms, and the molar ratio of structural units derived fromethylene to structural units derived from α-olefin having 3 or morecarbon atoms (ethylene/α-olefin) is in the range of from 100/0 to 40/60.3. A hot melt adhesive composition comprising: 100 parts by weight ofbase polymer (A), 10 to 300 parts by weight of tackifier (B), and 10 to400 parts by weight of ethylene/α-olefin/aromatic vinyl compound randomcopolymer (C), wherein in random copolymer (C), the α-olefin has from 3to 20 carbon atoms, and the molar ratio of structural units derived fromethylene to structural units derived from α-olefin having 3 or morecarbon atoms (ethylene/α-olefin) is in the range of from 100/0 to 40/60.4. The hot-melt adhesive composition as claimed in claim 2 or 3, whereinthe base polymer (A) is at least one polymer selected from the groupconsisting of a polyolefin (a-1), a polar group containing polymer (a-2)and an aromatic vinyl compound/conjugated diene copolymer (a-3).
 5. Thehot-melt adhesive composition as claimed in claim 2 or 3, wherein thebase polymer (A) is an aromatic vinyl compound/conjugated dienecopolymer (a-3).
 6. The hot-melt adhesive composition as claimed in anyof claims 1 to 3, wherein the ethylene α-olefin/aromatic vinyl compoundrandom copolymer (C) contains structural units derived from an aromaticvinyl compound in an amount of 1 to 80 mol %.
 7. The hot-melt adhesivecomposition as claimed in any of claims 2 or 3, which further comprisesa low-molecular-weight polyolefin having an intrinsic viscosity (η) of0.01 to 0.6 dl/g (D) in an amount of 1 to 100 parts by weight per 100parts by weight of the base polymer (A).
 8. The hot-melt adhesivecomposition as claimed in claim 1 which further comprises alow-molecular weight polyolefin having an intrinsic viscosity (η) of0.01 to 0.6 dl/g (D) in an amount of 1 to 100 parts by weight per 100parts by weight of the tackifier (B).
 9. The hot-melt adhesivecomposition as claimed in claim 8, wherein theethylene/α-olefin/aromatic vinyl copolymer (C) contains structural unitsderived from aromatic vinyl compound in an amount of 1 to 80 mol %. 10.The hot-melt adhesive composition as claimed in claim 1, 2 or 3, whereinin random copolymer (C) the molar ratio of structural units derived fromethylene to structural units derived from α-olefin having 3 or morecarbon atoms (ethylene/α-olefin) is within the range of from 100/0 to60/40.
 11. The hot-melt adhesive composition as claimed in claim 1, 2 or3, wherein in random copolymer (C) the molar ratio of structural unitsderived from ethylene to structural units derived from α-olefin having 3or more carbon atoms (ethylene/α-olefin) is within the range of from100/0 to 70/30.
 12. The hot-melt adhesive composition as claimed inclaim 1, 2 or 3, wherein the random copolymer (C) comprisesethylene/styrene random copolymer.
 13. The hot-melt adhesive compositionas claimed in claim 1, 2 or 3, wherein the random copolymer (C)comprises ethylene/butylene/styrene random copolymer.